The myth of the noble savage dates from the 1700s. The idea was that primitive natives, unspoiled by the vices of (typically European) settlers, were "better" than civilized men. "Pity for the vanishing Indian, together with a sense of remorse, led to a revival of the 18th-century concept of the noble savage. America's native inhabitants were romanticized in historiography, art, and literature, notably by James Fenimore Cooper in his Leatherstocking Tales and Henry Wadsworth Longfellow in his long poem, The Song of Hiawatha."  Jean-Jacques Rousseau famously extolled the virtues of man in a state of nature, writing at great length of the virtue and superiority of man in an uncivilized state.
Noble savage and Christianity
The Myth of the Noble Savage is incompatible with Christian teachings. When Adam and Eve ate the apple they fell from grace, as did all their descendants. Only through holy communion with Jesus can man ascend beyond his sinful nature.
It can be argued that the "noble savage" myth actually implies paganism and primitive native lifestyles as being more preferable and noble than the Bible's teachings. This argument explicitly and directly contradicts the Bible and the morally superior Christian lifestyle and is often promoted by atheistic anthropophobiacs.